package org.apache.lucene.analysis;

/**
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/**
 * Removes words that are too long and too short from the stream.
 *
 * @author David Spencer
 * @version $Id: LengthFilter.java 347992 2005-11-21 21:41:43Z dnaber $
 */
public final class LengthFilter extends TokenFilter {

    final int min;
    final int max;

    /**
     * Build a filter that removes words that are too long or too
     * short from the text.
     */
    public LengthFilter(TokenStream in, int min, int max) {
        super(in);
        this.min = min;
        this.max = max;
    }

    /**
     * Returns the next input Token whose termText() is the right len
     */
    public final Token next() throws IOException {
        // return the first non-stop word found
        for (Token token = input.next(); token != null; token = input.next()) {
            int len = token.termText().length();
            if (len >= min && len <= max) {
                return token;
            }
            // note: else we ignore it but should we index each part of it?
        }
        // reached EOS -- return null
        return null;
    }
}
